Blonsky's formula was based on Cap's serum (I think it was initially meant to be the exact same formula, in fact). He was moving inhumanly fast and was at least strong enough to hold a full grown man over his head casually. Even when he got kicked into that tree by Hulk, he healed in about a day.

Not much more than what's already been stated. It's just that little bit places him quite a bit above Matt.

It should be noted that he was a top British special forces guy that the US military employed for his skills for the sole mission of capturing Banner. He was able to support give Hulk's first attack before he ever got powers. He should be a decent fight for Matt without the serum. He strikes me as maybe around Punisher's skill level.

I never saw this movie but have heard of this scene. Is there a reason why Blonsky tried to commit suicide by Hulk by letting himself get kicked?

His arc was that he wanted to get more power and be more powerful, which is why he got the serum injection in the first place. He was actually juking the Hulk in close quarters and felt like he was getting the upper hand because the Hulk literally did not land a single hit on Blonsky.

When the Hulk eventually broke free of the trap and wrecked everything, Blonsky walks up to the Hulk, pulls out his earpiece (Ross is yelling at him to pull out) and insults the Hulk, which causes the Hulk to kick him.

Basically, the dude is on a power trip and wants to be even more powerful and the strongest one there is (which is why he gets the dude who is the future Leader to do that gamma modification or whatever)